Pneumatic clutch



PNEUMATIC CLUTCH Filed Nov. 16, 1943 9 Sheets-Sheet 4 BY I j Z L/74 z I ATTORNEY July 3, 1945. R 5 PHlLBRlCK 2,379,592

PNEUMATIC CLUTCH Filed Nov. 16, 19 43 9 Sheets-Sheet 5 INVENTOR.

1 -11211: EFT ELP'hi'LbT'i ck July 3, 19 5- R. s. PHILBRICK PNEUMAIIG CLUTCH Filed NOV. 16, 1943 9 Shee s-Sheet 6 226 Rob EFT E..F IT1'L IIIPLER 4 5 ATTORNEY-S.

July 3, 1945. R s, PHILBRlCK 2,379,592

PNEUMATIC CLUTCH Filed Nov. 16, 1943 9 Sheets-Sheet? INVENTOR.

E m l: EFT E1- Phi [Brick July 3, 19 R. s. PHILBRICK PNEUMATIC CLUTCH Filed Nov. 16, 1943 9 Sheets-Sheet 8 INVENTOR.

a; 6'0 1:]: art El. PH'LUJI 'L clc R. S. PHILBRICK PNEUMATIC CLUTCH July 3, 1945.

Filed Nov. 16, 1943 r? gg-E gas.

9 Sheets- Sheet 9 Hlll lH INVENTOR.

R Uh EFT E. Philbrick Patented July 3, 1945".

UNITED STATES PATENT OFFICE PNEUMATIC CLUTQH Robert s. Philbrick, York, Pa. Application November 16, 1943, Serial No. 510,533

13 Claims. The present invention relates to motion transinittlng means, and particularly to clutches of the pneumatic type adapted to transmit motionof a motor, engine or other power unit to a load.

moving, or other work performing mechanism.

The principal objects of the invention are to provide a pneumatic clutch operating by trap ping and compressing bodies of air, or gas, until such time that the air pressure equals the torque of the force to be overcome; and to provide a clutch which will overcome starting inertia and have the necessary power rang to gradually impose the load on the power unit without shock or vibration. Ina practical application ofthe invention, the clutch operates as a compressor, compressing air until the pressure thereof equals the torque of the force to be overcome, at which time the driving and driven unitsof the clutch rotate in unison.. This is in part accomplished by use of gate valves. againstwhich the air is compressed, and a control meanswhich may be selectively actuated bythe operator to cause the gatevalves to open thu allowing the air to flow freely without being trapped by the gate valves, and in effect disengaging the clutch. During the interval of time between that which is generally termed the disengaged and engaged conditions of the clutch, the load is being picked up, so to speak, thru a compressible and expansible medium such as air. Variations in the load are thus absorbed so that the motor or drive shaft is not directly subjected to such fluctuating loads, and the operator cannot subject the motor or prime mover to sudden load as with friction and some types of oil or liquid clutches.

Another. object of the invention is to provide clutches which may be easily manufactured and which will remain -in good -repair for a considerable length of time especially when air, which may be taken from and exhausted into the atmosphere, is used, due to. its cooling properties.

While I am aware that clutches using liquids, such as oil, as a driving medium have been proposed and used, it has been found that they are affected by temperature changes which render them 'very quick acting and difllcult to operate when cold, or ineflicient when warm or hot, if

suflicient clearance is allowed for use of a viscous liquid, such as cold oil. Another object of the invention is therefore to provide clutches which use air or gas as a driving medium thus avoiding Figure 2 is a fragmentary viewipartlyin end elevation and partly in vertical section of the clutch, showing more particularly a path which air may take entering the clutch, and gearing forming a part of means for compressing air in the clutch.

Figure 3 is a view mainly in central vertical section, longitudinally of the axis of the clutch,

some parts being shown in elevation to disclose preferred details.

-Figure 4 is a vertical cross-sectional'view on the line x-a: of Figure 3, looking in the direction of the arrows 4-4, but with the clutchin the so called disengaged condition.

Figure 5 is a view similar to Figure 4, but look-- ing in the direction of the arrows 5-5 on the line a:-a: of Figure 3, a portion of one of the elements being broken away to disclose details.

Figure 6 is a view similar to Figure 5 but showing the clutch in the so called engaged condition.

Figure ,7 is a vertical cross-sectional view on the line 11-11 of Figure 3, looking in the direction of the arrows.

the undesirable characteristics of liquidclutches. Other objects and advantages of the invention will appear in the following detailed description of the preferred embodiment of my invention, taken in' connection with the accompanying drawings, forming a part of this. specification,

and in which drawings:

Figure 1 is a side elevation of the clutch.

I driving rotary unit.

' line |6-l6 of Figure 15.

Figure 8 is a fragmentary sectional view on substantially the line 8-8 of Figure 5, looking in the direction of the arrows, to show a path air may take to exhaust the pressure chamber of the clutch and render it disengaged.

' Figure 9 is a fragmentary sectional view on substantially the line 99 of Figure 6, looking in the direction of the arrows, to show the manner in which air in the pressure chamber may find its way to assist in rendering the clutch operative as a motion transmitting medium, and cannot find egress to the atmosphere surrounding the clutch.

Figure 10 is a plan view of a drive shaft of the Figure 11 is an inner end elevation ber shown in Figure 10.

Figure 12 is a view partly in elevation and partly in vertical section thru a driven shaft of the driven rotary unit.

Figures 13 and 14 are cross-sectional views on the lines l3-I3 and tively.

Figure 15 is an end elevation, on a reduced of the mem 'scale of one of the parts of the driven unit.-

Figure 16 is a vertical sectional view on the Figure 1'? is an outside end elevation on a. re-

duced scale of another part of the driven unit.

Figures 18 and 19 are sectional views on the lines l8-l8 and Iii-I9, respectively, of Figure 1'7. Figure 20 is an outside elevation on a reduced scale of a coverplate for the unit shown in Fig- Figure 21 is a, sectional view on the line Il il ofFlgure20.

I l-l4 of Figure 12, respecside of the body part 54, a chambered portion 5'! to the other side of body part 51, ring-like guide plates 58 and 59 cooperating with and acting as tracks for the side plates 52 and 53, respectively,"

and a driven shaft 60. The hub element or rotorbody 5| and side plates 52 and 53, of the rotary driving unit, and the annular body part 54 and guide plates 58 and 55 cooperate to provide the annular. airway C in which parts of means F operate, as shown in Figure 6, to draw in air and .compress same when changing from a disen- Figure 28 is an end elevation, on a reduced scale, of a hub element forming a part of the rotary driving unit.

Figure 29 is a sectional view on the line 29-29 of Figure 28.

Figure 30 is a view in end elevation, on a reduced scale, looking toward the inside of one of the side members associated with the hub element shown in Figure 28.

- Figures 31 and 32 are sectional views on the lines 3|-3| and 32-32, respectively, of Figure 30.

Figure 33 is a view similar to Figure 30 but looking toward the outside face of another side member associated with the hub element shown in Figure28.

Figure 34 is a sectional view on the line 34-34 of Figure 33.

Figures 35 and 36 are perspective views looking at different sides and ends of a rotary barrier element associated with the rotary driving unit of the clutch.

' Figures 3'7 and 38 are perspective views looking at different sides and ends of a gate valve associated with the rotary driven unit of the clutch.

' Figure 39 is a sectional view on the line 39-39 of Figure 37.

gaged to an engaged" condition, and in which parts of means F idle when changing from an engaged to a disengaged condition, as shown in Figures 4 and 5.

The chambered portion 51 of the rotary driven unit Bis preferably made up of a body part 52 shown more in detail in Figures 17-19, and a cover 63, shown more in detailin Figures 20 and 21, the body part 62 including an inner annular portion 64, an outer annular portion 65, and a wall 65 joining the portions 54 and 65 so as to provide with the cover 63, the annular pressure chamber D. The wall 65 is disposed nearest the airway C and is provided with a plurality of major transverse ports 68 spaced equidistant from each other and from the axis of the clutch, and laterally of the airway C. It is thru ports 68 that air compressed in airway C finds its way to chamber D. The wall 66 is also provided with a plurality of minor transverse ports 69, also spaced lines 42-42 and 43-43, respectively, of Figure- Figure 44 is an end view of a shifting element forming a, part of the control means. Figure 45 is a side elevation of the shifting element, a part being broken away and shown in section.

Figure 46 is a plan view or one of the shifting elements.

In the drawings, A designates a rotary driving unit, and B, a rotary driven unit, providing an annular airway C, the driven unit B including an air pressure chamber D; F means carried by the units A and B to alternately draw air into the way C and compress same when there is relative movement between the units A and B; G means for controlling passage of compressed air from the airway C to the compression chamber D; and, H means for controlling exit of air from the compression chamber D, and in one position, closing of! communication between the airway C and compression chamber D, as shown in Figure 5.

The rotary driving unit A includes, in the example shown, a drive shaft 56, a hub element or rotor body 5| and side plates 52 and 53; while the equidistant from each other and from the axis of the clutch, provided for egress of air from pressure chamber D.

The wall 66 is spaced from the adjacent side plate 53 of the rotary driving unit A and from the ring-like guide plate 59 of rotary driven unit B, as shown in Figure 3, to accommodate a valve plate 10, shown more in detail in Figures 41-43, forming'a part of means H. It is this valve plate HI, the means G (Figure 33) carried by side plate 53, characteristics of the guide plate 55 (Figures 2427) and characteristics of the chambered body 51 (Figures 17-21) that control entrance of air from the airway C to the pressure chamber D; exit of air from the pressure chamber to the atmosphere; and, for service in emcient operation of the clutch.

The means F for alternately drawing air into the airway C and compressing the same, when there is relative movement between the driving and driven units A and B, comprises a plurality of rotary barriers 1|, carried by the driving unit A; a plurality of gate valves 12 carried by driven unit B; and'gearing I3 carried by units A and B for operating the barriers I Preferred characteristics of the rotary driving unit A are as follows:

The drive shaft 50 as shown in Figures 3, 10 and 11 is provided with an enlarged inner end portion 14 having a cavity 15 for receiving an anti-friction bearing 11, the inner race 18 of which assists in supporting the driven shaft 50 as hereinafter described. The hub element 5| and side plates 52 and 53 are secured together by bolts 19 extending thru holes in element 5| and having its'end portions accommodated in holes 8| and 82 in the side plates 52 and 53, respectively. There may also be provided dowel pins 83 extending thru holes 84 in element 5| and having their ends accommodated in recesses 85 and 88 in-the side plates 52 and '53, respectively. The side plate 52 is provided with a central opening 81 to fit the end portion 14 of drive shaft 50, suitable keys 36 being accommodated These ribs are rectangular inan inner track face 94 concentric with the ringlike portion 9 I. The ribs 92 are inset with respect to the opposite side faces 95 of the latter to provide recesses 96 and 91 for accommodation of portions of the guide plates 58 and 59, respectively. The ends 98 of ribs 92, at the spaces between the ribs, are parallel and cooperate with the guide plates 58 and 59 to provide pockets 99 to accommodate the gate valves 12. Suitable transverse holes I are provided to accommodate the shanks IOI of bolts I02 used to connect various parts of the rotary driven unit.

The gear cover plate 55, shown more in detail in Figures 2 and 3, comprises a disc-like body part I03, encircling a portion of drive shaft 50 andprovided with a plurality of transverse air inlet holes I04; an inwardly extending annular flange on the body part I05 confronting the side face 95 of annular body part 54 and presenting a recess I06 for accommodating a part of the ring-like guide plate 58; an enlargement I01 of the body part, about the drive shaft 50, accom- 7 modating an antifriction bearing I08 which also engages the drive shaft 50; and a relatively large internal gear I09 forming a .part of the gearing j 13. The gear cover-plate 55 is also provided with screw-threaded sockets IIO for accommodatingthe screw-threaded ends I II of bolts I02.

The body part 62 of chambered portion 51 in addition to the characteristics above described,

is provided with an annular flange I I2, similar to flange I05 confronting the other side face 95 of annular body part 54 and presenting a recess II3 for accommodating the ring-like guide plate 59. Also the wall 66 is inset with respect to re= cess II3 to provide another smaller annular recess II4 for accommodation of a portion of the valve plate 10. The outer annular portion 65 is provided with transverse holes II5 for accommodation of the shanks IOI of bolts I02 and the inner annular portion 64 is provided with screwthreaded sockets II6 for receiving the threaded shanks of bolts II1 used to assist in securing the cover 63 to the body part 62. Another important characteristic 'of the body part 62 is that it is provided with a plurality of air outlet ports II8, spaced equidistant from eachother and from the axis of the chambered portion 51. As shown in Figures 8, 9 and '19, these ports II8 each have an inlet end II9 open to the annularwall I of recess H4, and an outlet end I2I open at the face I22 that confronts cover 63.

The cover 63 comprises a disc-like body part I23 and a hub I24, the opening I25 .of which encircles the driven shaft 60 and is keyed there-' part I23 has, near its rim, recessed holes I21 to accommodate the shanks and heads of bolts I02;' recessed holes I28 near hub I24 to accome mod'ate the shanks and heads of bolts H1; and

, outlet ports I29 to align-with the outlet ends I2I of ports H8. The hub I24 has a transverse to receive a portion, of the key I26, there being a radial screw-threaded bore I3I in the .hub to place. There is also provided in hub I24 a plurality of transverse slide ways I33, communicating with opening I25 fora purpose to be subsequently set forth.

The ring-like guide plate 58, shown in detail in Figures 22 and23, has opposite parallel side faces I34 and I35. The face I34 cooperates with the ribs 92 of annular body part 54 (Figure 15) to provide one end wall I36 for each of the pockets 99, Open to the zones of face I34 which thus serveas end walls I36 are radial grooves I31 also open to the outer periphery I36 of the plate 58 and terminating shortof the inner periphery I39 of said plate to provide abutments I40. Open to each of the grooves I31, near the abutment I40 thereof, is a transverse air inlet port MI. The side of plate 58 opposite to sidewall .I34 has-a recess I42 to. accommodate the major portion I43 of side plate 52, the "minor portion I44 of the plate 52 being accommodated in the opening defined by the inner'periphery I39 of the plate 58. Arcuate recesses I45 are open to the outer periphery I38 to accommodate the its companion plate 58 in'that its one face I46 The side plate 53 of the rotary driving unit is partly accommodated in the opening defined by the inner periphery I50, as shown in Figure 3.

However, the ring-like guide plate 59 is so made as to assist in controlling entrance of air to the pressure chamber D, exit of air therefrom to the pockets 99 and to the atmosphere, and to accommodate characteristics of means H. Open to each of the. grooves I48 is a radial slot I53 also open to the other face I54 of the plate 59. Each slot serves to accommodate a pin I55 associated with the adjacent gate valve 12 and the valve plate 10, as shown in Figure 3. Another characteristic of the ring-like plate 59 is that it has r a number of transverse ports I56 atits-lnner portion at all times axially aligned with the major ports 68 in thewa'll 66 of body part 62 as shown in Figure, 6 where in the lower left side of the view one of the ports I56 is shown open to a port 68. A further characteristic of] plate 59 is that it has a major recess I51 defined by a peripheral flange I58 and a face I59 for ac- ;to as by key I26 shown in Figure 1. -The body commodating a portion of the valve plate 10, and a minor recess I60 inwardly of the plane of face I59 and defined by circular wall I6Iand face I62 for accommodating the control means G. Still another characteristic of plate 59 is that it has ports I63, corresponding in number to the number of minor ports 69 inbody part 62, for delivering air under pressure to each of the pockets 99, to act upon the gate valve 12 therein when the clutch is'operating to transmit motion from the driving shaft to the driven shaft. The

receive a set screw I32 to hold the key, I26 in Arcuate re'cesses entrance ends I88 of ports I83 are axially aligned with the minor ports 88 and are open at the face I58 as shown in Figures 8, 9 and 26, and the outlet ends I64 are open to the radial grooves I48 and slots I83. Merely by way of example, to facilitate manufacture the outlet portions I64 of the ports I63 may be made by milling arcuate grooves I65 in the pheripheral face I 48 open to the grooves I48 and slots I58, drilling holes I66 partially thru the plate from the face I58 to provide the entrance portions of the ports I63 and connecting grooves I65 and holes I58 by holes I61 drilled radially of the plate as shown in Figures24 and 26.

The driven shaft 60 shown more in .detail in Figures 12-14, comprises-a main shaft portion I10 and a reduced stub shaft portion III. The portion I10 is shown provided with a socket I12 for receiving any part, not shown in the drawings, to be driven thereby. It also has a recess I13 for the key I26 whereby the cover 63 is keyed to the driven shaft, and a plurality of longitudinally extending grooves I14 open to its external periphery to accommodate parts of the control means G. The stub shaft portion, at its free end, receives the inner race 18 of anti-friction bearing I1, Another anti-friction bearing H5 is also interposed between the stub shaft portion adjacent its juncture with the main shaft portion I10, and the inner periphery I16 of side plate 63, The bearings 11 and H5 serve to rotatably support the rotary driving unit A on the driven shaft when the clutch is in adisengaged condition.

Referring now to the means F for alternately drawing air from the atmosphere into the way C and compressing same, as previously set forth it includes the rotary barriers II, the gate valves 12 and gearing 13. An example of the rotary barrier H is shown in perspective in Figures and 36, and in cross section in Figures 4, 5 and 6. It is in the nature of a cylinder having an axial bore I80 for receiving its supporting shaft I8I, to which it may be secured by a set screw I82, received in a radial screw-threaded bore I03, or in any suitable manner; and a pocket I84 shaped somewhat like. the space between the teeth of an ordinary gear wheel. The ends of shaft I8I may besupported by the inner races of anti-friction bearings I85 and I86, the outer races of which are received in recesses I81 and I88 of the side plates 52 and 53, respectively, there being holes I88 and I80 in the said plates thru which the end portions of the shaft extend. In order to accommodate the rotary barriers II in the hub element or rotor body 5I, with which they are carried, the latter is provided with substantially semi-circular recesses I8 I, in the examples shown, diametrically opposite one another, to accommodate two of such barriers. These barriers are in substantially fluid tight engagement with their respective recesses, with the side plates and 53, and with the guide plates 58 and '58. They are also arranged to have substantially fluid tight engagement with the track face I4 of the annular body part 54, whereby they III III

divide the airway C into chambers I82 and I83 as shown more particularly in Figure 4.

The gearing I3 is provided as positive motion transmitting means to cause the barriers II to rotate with respect to the hub whenever there is relative movement between the driving unit and the driven unit. This gearing includes the internal gear I08 and pinions I84, meshing therewith, there being one pinion on each shaft IBI,

aevaaee located between the gear cover 55, the side plate 52 and the guide plate 58, as shown in Figures 2 and 3. The pitch diameters of the gear I08 and pinions I84 is such that if the rotary driven unit B is inert, its internal gear I08 will cause one complete revolution of each rotary barrier 'II with respect to the rotor body 5I'ior each gate valve 12 in the assembly, during one complete revolution of the rotor body 5I. In the example shown there are two rotary barriers II and three gate valves I2, so that under the conditions mentioned, each rotary barrier will make three complete revolutions with respect to the rotor body 5|, for each revolution of the latter.

As to the gate valves I2, each is formed to include a tooth-like body portion I85 having opposite side faces I86 and I8'I for engagement with the walls of pockets I84 inthe rotary barrier II, and a root face I88 for engagement with the circumferential face of the rotary body 5|, when this tooth-like body portion is not in a pocket of a rotary barrier II, but functions to divide the chamber I82 into subchambers I88 and 200, and the chamber I83 into subchambers 20I and 202, as shown in Figure 6. Each gate valve also includes a piston-like portion 203, slidable in pocket 88 and end guide ribs 204 and 205 slidable in the grooves I31 and I48 of guide plates 58 and 58, respectively. Since centrifugal force will tend to throw the gate valves to an unseated positionas the rotary driven unit B gains speed,

I prefer to provide at least one expansion spring 208 for each gate valve, located in pocket 88 therefor, having its one end abutting against the ring-like outer portion 8I of annular body part 54 and its other end portion accommodated in a recess 201 in the piston-like portion 203. Each spring 206 has just sufficient strength to slightly overbalance the weight of its respective gate valve, so as to normally cause the valve to seat when there is no air above atmospheric pressure in the pocket, acting upon the piston-like portion 203 of the valve and the rotary driven unit B is either inert or rotating at a low speed.

Each gate valve has an air inlet port 208, the entrance end 208 of which is open at rib 204 and the outlet end 2| 0 open at side face I86. The entrance end 208 is so located that, when the gate valve is seated, it is open to the adjacent port MI in the guide plate 58, as shown in Figure 3, thus enabling air to be taken into the subchamber of the airway C as the adjacent rotary barrier II moves away from the gate valve (see subchamber 202, Figure 6). The other rib 205 isconvenientlyprovided with a recess 2 near its upper end for accommodation of the pin I55 as shown in Figure 3. It is obvious from this description that if there is atmospheric pressure in the pockets 88 and the rotary driven unit B is rotating at a high speed, centrifugal force will throw the gate valves to open positions as shown in Figures 4 and 5, thus leaving nothing in the airway C to divide the chambers I82 and I83 into subchambers and the clutch is then in a so called disengaged condition. In fact if an outward force is exerted upon the pin I55 of each On the other hand if there is no mechanical means acting upon the pins I55 to retain the gate valves open, and there is atmospheric pressure inlthe pockets 88, with the rotary driven unit inert, the gate valves will assume a closed position, due to the expansion springs 206. This will result' in subchambers being formed in the the torque of the force to be overcome.

airway C. If the driving unit is then rotated, air will be. drawn into the airway C and compressed, and the function of the means G is to control passage of the air from the airway C to the compression chamber D. In the example shown, it comprises two arcuate, flange-like valve segments 2I2 and 2I3, formed integral with the side plate 53 of the rotary driving unit A, and accommodated partly in the minor recess I66 in the guide plate 59, and partly in the recess 2 in the valve plate 16. The valve segment 212 and 2 I 3 are spaced apart to provide gaps 2 I 5 and 2 I5 The deflecting keys 2 I8, each have a body portion 221, rectangular in cross section, a shifting lug 228 extending from one longitudinal face of the body portion 221 at one end, thereof, and a spiraliform lug 229 extending from the same face as lug 228 but at the opposite end of the body portion 221, as shown in Figs. 3 and 46. The body portions 221 of the deflecting keys 2I6 .are 1 accommodated partly in the grooves I'M of and the segments are of such length as to permit only one port I56 (or the partial area of two of such ports I56 equal to the total area of any one of the ports I56), to be open to the pressure chamber D at any one time, and thenonly if the valve plate 16 permits ofsuch, as hereinafter described.

For instance in Figure 6, assuming that the rotary driving unit A is moving in the direction indicated by the arrow, and the rotary driven unit B is rotating at a slower speed, the port I56 open to subchamber I99 in also open to a port 68in the wall of the pressure chamber because the gap 2I5 between the valve segments 2I2 and 2I3, permits this, and therefore air compressed between the barrier II and gate valve, may find its way to the pressure chamber D. However the port I56, open to subchamber 266 is closed from communication with the pressure chamber D, by valve segment 2l2. Also the port I 56 in subchamber 26I is likewise closed by valve segment 2I3. In Figure 6 we therefore find sub-- chamber I99, delivering air under pressure to the chamber D; subchamber 266 at atmospheric pressure; subchamber 26I with air very slight ly undercompression; and, subchamber 262 at atmospheric pressure, or nearly so, since pair is being sucked into it as by the barrier II moving away from the trailing gate valve I2. If, how.- ever, the pressure in chamber D has equaled the torque of the .force to be overcome, the rotary driven unit B will rotate in unison withunit A and subchamber 262 will not take in any more air from the atmosphere until the load becomes greater whereupon there will again be relative movement between the units A and B, until they pressure in chamber D has again equaled If the the driven shaft, partly in the slide ways I33 ofv cover 63, and partly in the notches 226 in collar 2I9. The shifting lugs 226 are received. in groove 223 of collar H9 and abut against flange 225. The spiraliform lugs 229 fit in-the spiral grooves 2II of hub 2I6. It is thus apparent that even tho the driven shaft 66 is rotating the valve plate I6 may be moved circumferentially according to the pitch of the spiral grooves 2 I l in its hub by moving the spiraliform lugs longitudinally of the driven shaft thru shifting yoke 22I, collar 2I9, and deflecting'key 2I8.

Other characteristics of the valve plate '16 are shown in Figures 41-43. The main body 236 has thru ports 23I open to the recess 2. These ports 23I are spaced apart from each other and from the axial center of the valve plate exactly like the ports 69 in the wall '66 of body part 62. Therefore if the valve plate is in a position for rendering the clutch operative as a motion transmitting medium, these ports 68 and 23l, as well as the .ports I56 are all axially aligned. 'Howv includes concentric portions 233, separated by cam portions 234, which start at shoulders 235 and gradually curve outwardly to constitute cam throws merging into the concentric portions 233. It is on these cam portions that the pins I55 ride, so as to positively unseat the gate valves 12. The rim 232 has ports 236 spaced apart from each other and from the axial center of the valve plate, the same asthe inlet ends I69 of ports I63 and with the minor ports 69 in body 62, whereby air from pressure chamber D may get thru ports 69', 236 and I63 to the pockets 99 as shown in Figure 9 and thereby hold the gate valves I2 closed.

load becomes lighter,'the compression subcham- I ber I99 will become enlarged and air will be forced from the subchambers 266 and 262.

This is of course the relationship of those ports when the clutch is operating as a motion transmitting medium.v At that time port II3 to the atmosphere is closed by .a concentric portion 233 of valve plate 16, as shown in Figures 6 and 9.

.-The rim 232 also has elongated, arcuate thru Finally in connection with the means H, in addition to the valve plate 16 which in the example 'shown includes a hub 2I6 rotatable in the inner annular portion 64 of body part 62, and has on its internal periphery spiral grooves 2II corresponding in number to the number of grooves I14 in shaft 66; a deflection key 2I3 for each of the companion grooves I14 and 2I'I, a shifting collar 2I9' slidable longitudinally on driven shaft 66, and having a peripheral groove 226,

and a clutch yoke 22I pivoted as at 222, and opcrating in the usual way to move thecollar longitudinally of the drivenshaft while the collar rotates therewith. The collar 2I9 has an internal circumferential groove 223 providing internal circumferential flanges 224 and 225, the

, former of which has three notches 226, as shown centric therewith.

ports 231 struck at the same radius, from the axis of the valve plate, and radial ports 238 open to ports 23Ifand cam surfaces 234, asshown in Figure 41. The elongated arcuate ports 23'! are so located as to open to the ports 69 in body 62,

when the valve plate has been shifted to release the clutch, as shown in, Figure 8,-whereby air in pressure chamber D may reach the atmosphere and air in the valve gate pockets 99 is released thru ports H9 and I29.

It is believed the operation of the pneumatic clutch may well be understood from the foregoing, but briefly it may be statedthat air is taken 7 in thru ports I64 (Figures 2 and 3) when the ro- A tary driving unit A is picking up the load, the

air circulating around the gearing" and entering airway C thru ports I and 269, the latter being in the gate valves I2. The air is alternately taken in and compressed by the rotary barriers 'lI cooperating with the gate valves I2 and is accumulated in'pressure chamber 'D by successive opening and closing of the ports 6,131 and 63 as thru the means G.

While the gate valves 12 are initially held closed by springs 206, when the clutch is set into operation, they are maintained elosed against centrifugal action as the driven unit B gains speed, by some of the air under pressure finding its way thru the ports shown in Figure 9 to the pockets 99 where it acts upon the piston-like portions 203 of the gate valves.

When it is desired to release the clutch, the yoke MI is operated to shift the valve plate from the position shown partly by full and partly bydotted lines in Figure 6, to the position similarly shown in Figure 5. The first effect during this shifting of the valve plate is to cut off communication between the pressure chamber D and the pockets as by ports 236 in the valve plate moving out of alignment with ports 69 in the wall of the pressure chamber. Upon further movement of the valve plate, the ports 21 in the valve plate III are moved out of alignment with ports I56 in the guide plate 59 and ports 68 in the wall 66 of the pressure chamber. Directly as this occurs, the concentric portions 233 of the rim 232 of valve plate uncovers exit ports H6 and I29 (Figure 8) and air under pressure in pockets 99 is released allowing the gate valves to open due to centrifugal force. This then frees the airway C of subchambers, and the rotary barriers cease to operate as compressor elements and merely idle in the airway C. Further movement of the valve plate Ill results in the ports 68 opening with arcuate ports 23! in the valve plate, and air in the compression chamber is released to the atmosphere as shown in Figure 8 thru ports 231, 238, H6 and I29. Finally the valve plate 10 may. be

moved to a position where the throw sides of cam surfaces 236 will, by engagement of the pins I55, on the gate valves, therewith, positively move the gate valves to an open position should they become stuck, and will positively hold the gate valves in an open position when the clutch is in a "disconnected" condition.

To start the clutch as a motion transmitting medium, the shifting yoke MI is moved to shift the valve plate in a direction to release the gate valves, so they will close responsive to springs 206, and so that air may get from the airway C to the pressure chamber D where it is builtup, having no egress to the atmosphere.

While in the specification reference is' made to air as a motion transmitting medium, it is of course understood that any suitable gas or vapor may be used, without departing from the spirit of the invention. Also while unit A is designated a driving unit and B a driven unit, it is to be understood that instead, motion may be imparted airway into to the unit B by the prime mover'or motor and the unit A receive motion from unit B, without departing from the spirit of the invention altho it is preferred that the unit B remain inert when the clutch as a whole is not acting as a motion transmitting means.

I claim: 1. In a pneumatic clutch, the combination of a rotary driving unit and a rotarydriven unit providing an annular airway; means carried by said units to alternately draw air into said way and compress same when there is relative movement between said units, said driven unit including an air pressure chamber, one wall of which is provided with a port for transfer of the compressed air to said pressure chamber; and said driving unit including a valve portion rotatable therewith, cooperating with said wall to close said port when air is being drawn into said aircut of! communication rotary barriers in spaced relation,

driving unit, disposed in said airway, and co airway into chambers;

a driving unit provided,

way and to open said port when air isbeing compressed in said airway, whereby; the units will rotate in unison when the air pressure in said chamber equals the torque of the force to overcome in the operation of the clutch.

2. In a pneumatic clutch, the combination of a rotary driving unit and a'rotary driven unit providing an annular way; means carried by said units to alternately draw air into said way and compress same when there is relative movement between said units, said driven unit including an air pressure chamber, one wall of which is provided with a port for transfer of the compressed air to said pressure chamber, and said driving unit including a valve portion rotatable therewith, cooperating with said wall to close said port when air is being drawn into said airway and to open said port when air is being compressed in said airway, whereby the units will rotate in unison when the air pressure in said chamber equals the torque of the force to be overcome in the operation of the clutch; and means to open said pressure chamber to the atmosphere to render the driven unit inert.

3. In a pneumatic clutch, the combination of a driving unit provided with a circumferential airway open to its periphery; a driven unit providing a circumferential outer wall for said airway; rotary barriers in spaced relation, carried by said driving unit, disposed in said airway, and cooperating with said driven unit to divide said chambers; and tooth-like gate valves carried by said driven unit, movable radially toward and away from the bottom of said airway, each provided with a root face for engagement with the bottom of said airway said rotary barriers provided with recesses to accommodate said gate valves when there is relative movement between said driving and driven units, and said gate valves, when projected into said airway between said barriers and disposed with their root faces engaging the bottom of said airway.- serving to divide said chambers into alternately changing suction and compression sub-chambers.

4. In a pneumatic clutch, the combination of a driving unit provided with a circumferential airway open to its periphery; a driven unit providing an outer circumferential wall for said airway, and including an air pressure chamber; carried by said driven unit to divide said gate valves carried by said driven unit, movable into and out of said airway, said rotary barriers provided with recesses to accommodate said gate valves when there is relative movement between said driving and driven -units, and said gate valves when moved into said'airway between said barriers serving to divide said chambers into alternately changing suction and compression sub-chambers; and valve means operative upon relative movement between said driving and driven units to permit air to flow from the compression subchambersto the air pressure chamber and to between the suction subchambers and said air pressure chamber.

5. In a pneumatic clutch, the combination of with a-circumierential airway open to its periphery; a driven unit providing an outer circumferential-wall for said airway, and including an air pressure chamber: rotary barriers in spaced relation, carried by said driving unit, disposed in 'saidairway, and cooperating with said driving unit provided ing unit, disposed insaid'airway,

driven units to permit ,ber and to permit air under operating with said driven driven unit, movable into and out of said airway, said'rotary barriers provided with recesses to accommodate said gate valves when there is relative movement between said driving and driven units, and said gate valves when moved into said'airway between said barriers serving to divide said chambers into alternately changing suction and compression sub-chambers; valve means operative upon relative movement between said driving and driven units to permit-air to flow from the compression sub-chambers to the air pressure chamber and to cut oif communication between the suction sub-chambers and said air pressure chamber; and, second valve means -to cut ofi' communication between said chambers and said air pressure chamber an open the latter to the atmosphere.

' 6. In a pneumatic clutch, the combination of a driving .unit provided with a circumferential airway open to its periphery; a driven unit providing an outer circumferential wall for said airway, and including an air pressure chamber; rotary barriers in spaced relation, carried by said driving unit, disposed in said airway, and coopermosphere, and cut 011? communication between said chambers and said air'pressure chamber.

ating with said driven unit to divide said airway into chambers; gate valves carried by said driven unit, movable into and out of said airway, said rotary barriers provided with recesses to accommodate said gate valves when there is relati e movement between said driving and driven units, and said gate valves when moved into said airway between said barriers serving to divide saidchambers into alternately compression sub-chambers; valve means operative upon relative movement between said driving and driven units to permit air to flow fromthe compression sub-chambers to the air pressure chamber and to cut of]? communication between the suction sub-chambers and said air pressure chamber; and second valve means, in one'p'osition to permit air'under pressure from said air pressure chamber to act upon said gate valves'to hold them into said airway,

the atmosphere.

7. In a pneumatic clutch, the combination of a with a circumferential airway open to its periphery: a driven unit providing an outer circumferential wall for said airway, and including an air barriers in spaced relation, carried by said driving with said driven unit to divide said airway into chambers; gate valves carried .by said driven changing suction andand in a second posi-' tion to release air in said air pressure chamber to pressure chamber; rotary.

and cooperatunit. movable into and out of said airway, said rotary barriers provided with recesses ,to accommodate said gate valves when there is relative movement between said driving and driven units,

and said gate valves when moved into said airway between said barriers serving to divide said chambers into alternately changing suction and, compression sub-chambers; valve means operative upon relative movement between said'driving and air to flow from the compression sub-chambers to the air pressure chamcut oil? communication between the suction sub-chambers and said air pressure chamber; and second valve means, in one position to chamber to act upon said into said airway, and in a. second position torelease air in said air pressure chamber to the atpressure from said air pressure 1 gate valves to hold-them circumferential outer ment between said 8. In a pneumatic clutch, thecombination of a driving unit providing a circumferential airway open to its periphery; a driven unit providing a circumferential outer wall for said airway and including an air pressure chamber; barriers carried by said driving unit in spaced relation, disposed in said airway and cooperating with said driven unit to divide said airway into chambers; gate valves slidable in cavities in said driven unit, movable radially into and out of engagement with the bottom of said airway, and when projected into said airway between said barriers, serving to divide said chambers into alternately changing suction and compression sub-chambers upon relative units; valve means operative upon relative move ment between said driving and driven units to permit air .flow from the compression sub-chambers to said air pressure chamber, and to cut off communication between the suction sub-chambers and said air pressure chamber whereby movement of the driving unit, is imparted to the driven unit as air pressure is built up in said pressure chamber; spring means in said cavities'of the driven unit, acting upon said gate valves to initially overcome movement thereof due to centrifugal force as the driven unit is rotated at low speed; and second valve means to admit air from --said pressure chamber to said gate valve cavities of the driven unit to overcome movement of said gate valves radially, due to centrifugal force when the driven unit 'is operating at a high speed.

9. In a pneumatic clutch, the combination of a driving unit providing a circumferential airway open to its periphei a driven unit provi in a wall for said airway and including an air pressure chamber; barriers car- .ried by said driving unit in s aced relation, disposed in said airway driven unit to divide and cooperating with said said airway into chambers;

gate valves slidable in cavities in said driven unit,-

movable radially into and out of engagement with the bottom of said airway. and when projected into said airway between said barriers, servingto divide said chambers into alternately changing suction and compression sub-chambers upon relative movement between the driving and driven units; valve means operative upon relative movedriving and driven units to permit air to flow from the compression subchambers to said air pressure chamber, and to cut-01f communication between the-suction subchambers and said air pressure chamber when movement of the driving unit is imparted to the driven unit as air pressure isbuilt up in. said pres-' sure. chamber; spring means in said cavities of the driven unit, acting upon said gate valves to initially overcome movement thereof due to centrifugal force as the driven unit is rotated at low speed; and second valve means, in one position adapted to admit air from said pressure chamber to said gate valve overcome movement of said gate valves radially, due to centrifugal force when thedriven unit is operating at high speed, and in another position to open sai'd cavities and said air pressure chamber to the atmosphere,

10. In a pneumatic clutch. the combination of a driving unit providing a circumferential airway open to its periphery; a driven unit providing a circumferential outer wall for said airway and including" an air pressure chamber; barriers carried by said drivin'g unitin spacedrelation, dismovement between the driving and driven I cavities of the driven unit to gate valve cavities of driven units provided mentioned means and posed in said airway and cooperating with said driven unit to divide said airway into chambers; gate valves slidable in cavitiesin said driven uni-t, movable radially into and out of engagement with the bottom of said airway, and when projected into said airway between said barriers, serving to divide said chambers into alternately changing suction and compression sub-chambers upon relative movement between the driving and driven units; valve means operative upon relative movement between said driving and driven units to permit air to flow from the compression subchambers to said air pressure chamber, and to cut off communication between the suction subchambers and said air pressure chamber whereby movement of the driving unit is imparted to the driven unit as air pressure is built up in said pressure chamber; spring means in said cavities of the driven unit, acting upon said gate valves to initially overcome movement thereof due. to centrifugal force as the driven unit is rotated at low speed; and manually operable mechanism includingvalve means, in one position adapted to admit air from said pressure chamber to said movement of said gate valves radially, due to centrifugal force when the driven unit is operating at high speed, and in another position to open said cavities and said pressure chamber to the atmosphere, and also including means to positive- 1y move said gate valves outwardly, out of engagement with the bottom of said airway, during movement from said first mentioned position to said second mentioned position.

11. A pneumatic clutch comprising a cylindrical driving unit provided with a circumferential airway open to its periphery; a driven unit empracing said driving unit, forming a circumferential outer wall for said airway, and provided with a pressure chamber; rotary barriers, in spaced apart relation, carried by said driving the driven unit to overcome unit, disposed in said airway and cooperating with said driven unit to divide said airway into chambers; gate valves carried by said driven unit, movable radially into and out of engagement with the bottom of said airway, said rotary barriers provided with recesses to accommodate said gate valves when there is relative movement between said driving and driven units, and said gate valves, when projected into said airway between said barriers, serving to divide said chambers into alternately changing suction and compression sub-chambers; a first means normally urging said gate valves inwardly into engagement with the bottom of said airway; and a second means for selectively moving said gate valves outwardly from engagement withv the bottom of said airway, said driven unit and gate valves provided with ports in communication for delivering air to said subchambers when acting as suction chambers during relative circumferential movement between said driving and driven units and when the gate valves are in an inward position, said driving and with ports in communication with one another and with said pressure chamber and open to -laid sub-chambers when acting as compression chambers, and said last the driven unit provided with ports in communication with each other, with said pressure chamber and with the atmosphere exteriorly of the driven unit, when said last mentioned means is operating to move said gate valves outwardly from engagement with the bottom of said airway.

12. In a pneumatic clutch, the combination of a driving unit providing a, circumferential airway open to its periphery; a driven unit providing a circumferential outer wall for said airway. having radially disposed cavities open to said airway; rotary barriers, in spaced apart relation, carried by said driving unit, disposed in said airway and cooperating with said driven unit to divide the airway into chambers; and gate valves slidably mounted in said cavities of the driven unit, movable radially into and out of engagement with the bottom of said airway, and when projected into said airway, between said barriers serving to divide said chambers into alternately changing suction and compression subchambers upon relative movement between the driving and driven units, said rotary barriers provided with recesses to accommodate said gate valves when there is relative movement between the driving and driven units and the rotary barriers pass said gate valve cavities, and said gate Valves each having a thru port with its one opening at one side face and its other opening at one end face thereof, the last mentioned opening communicating with a port in the driven unit open to the atmosphere, when the gate valve serves to divide the driving unit chambers into said subchambers, and the first said ports in the gate valves all facing in the same circumferential direction, whereby air may be taken into the airway as the said barriers move away from said gate valves and the air thus taken in is subsequently compressed against the side faces of the gate valves opposite-to said port openings in the gate valves.

13. In a pneumatic clutch, the combination of a driving unit providing a circumferential airway open to its periphery; a driven unit providing a circumferential outer wall for said airway and including an air pressure chamber; barriers carried by said driving unit in spaced relation, disposed in said airway and cooperating with said driven unit to divide said airway into chambers; gate valves slidable in cavities in said driven unit, movable radially into and out of engagement with the bottom of said airway, and when projected into said airway between said barriers, serving to divide said chambers into alternately changing suction and compression sub-chambers upon relative movement between the driving and driven units; valve means operative upon relative movement between said driving and driven, units to permit air to flow from the compression subchambers to said air pressure chamber, and to cut off communication between the suction subchambers and said air pressure chamber whereby movement of the driving. unit is imparted to he driven unit as air pressure is built up in said v pressure chamber; means in said cavities to slightly overbalance the weight of said gate valves and project them against the bottom of said airway to initially overcome movement thereof due to centrifugal force as the driven unit is rotated at low speed; and second valve means to admit air from said pressure chamber to said gate valve cavities of the driven unit to overcome movement of said gate valves radially due to centrifugal force when the driven unit is operating at a high speed.

ROBERT s. Pan-Baron mentioned opening of the 

